History

Rome had begun expanding shortly after the founding of the republic in the 6th century BC, though it did not expand outside the Italian peninsula until the 3rd century BC. Then, it was an "empire" long before it had an emperor.[5][6][7][8] The Roman Republic was not a nation-state in the modern sense, but a network of towns left to rule themselves (though with varying degrees of independence from the Roman Senate) and provinces administered by military commanders. It was ruled, not by emperors, but by annually elected magistrates (Roman Consuls above all) in conjunction with the senate.[9] For various reasons, the 1st century BC was a time of political and military upheaval, which ultimately led to rule by emperors.[6][10][11][12] The consuls' military power rested in the Roman legal concept of imperium, which literally means "command" (though typically in a military sense).[13] Occasionally, successful consuls were given the honorary title imperator (commander), and this is the origin of the word emperor (and empire) since this title (among others) was always bestowed to the early emperors upon their accession.[14]

Though the old constitutional machinery remained in place, Augustus came to predominate it. Although the republic stood in name, contemporaries of Augustus knew it was just a veil and that Augustus had all meaningful authority in Rome.[15] Since his rule ended a century of civil wars and began an unprecedented period of peace and prosperity, he was so loved that he came to hold the power of a monarch de facto if not de jure. During the years of his rule, a new constitutional order emerged (in part organically and in part by design), so that, upon his death, this new constitutional order operated as before when Tiberius was accepted as the new emperor. The 200 years that began with Augustus's rule is traditionally regarded as the Pax Romana ("Roman Peace"). During this period, the cohesion of the empire was furthered by a degree of social stability and economic prosperity that Rome had never before experienced. Uprisings in the provinces were infrequent, but put down "mercilessly and swiftly" when they occurred.[16]

The Barbarian Invasions consisted of the movement of (mainly) ancient Germanic peoples into Roman territory. Even though northern invasions took place throughout the life of the Empire, this period officially began in the IV century and lasted for many centuries during which the western territory was under the dominion of foreign northern rulers, a notable one being Charlemagne. Historically, this event marked the transition between the ancient world and the medieval ages.

The Romans, however, managed to stop further Islamic expansion into their lands during the 8th century and, beginning in the 9th century, reclaimed parts of the conquered lands.[29] In 1000 AD, the Eastern Empire was at its height: Basil II reconquered Bulgaria and Armenia, culture and trade flourished.[30] However, soon after, the expansion was abruptly stopped in 1071 with the Byzantine defeat in the Battle of Manzikert. The aftermath of this battle sent the empire into a short period of decline. Two decades of internal strife and Turkic invasions ultimately paved the way for Emperor Alexios I Komnenos to send a call for help to the Western European kingdoms in 1095.[26] Under the Komnenian restoration the state regained its strength.